Science Buddies: "Ask an Expert"

I am wondering if there is a way to avoid using hydrochloric acid to simulate stomach acid for experiments. I have read that lemon juice and vinegar have similar levels as stomach acid. Would lemon juice or vinegar work? If so, which is the better choice. If not, any other recommendations?

I hate to answer a question with a question, but why do you want to avoid using HCl?

Without knowing a lot more about what you are actually attempting to investigate, it is impossible to know if other acids might work.
Lemon juice contains 5-6% Citric Acid C6H8O7 (0.3M pH 2-3) which is a weak organic acid.
Vinegar is 4-18% acetic acid C2H4O2 is another weak organic acid.

Neither of these acids contains a Chlorine Cl ion and they both contain organic chains if that matters to the chemistry involved in your experiment.

Stomach or gastric acid is a combination of HCl, KCl, and NaCl which combined break down protiens (organic chains). If your experiment requires protiens to be acted upon, then organic acids are NOT going to work.